In many instances of vascular disease, a damaged, weakened, and/or enlarged portion of a blood vessel must be protected from intravascular fluid pressure. Continued exposure to such fluid pressure may result in progression of damage to the affected area and/or vessel failure, accompanied by significant morbidity or even sudden death. A well-established technique for treating such vascular damage is the use of transluminally-deployed stent grafts.
Briefly, a stent graft comprises two major components, a stent and a graft. The stent (one or more) typically takes the form of a somewhat stiff tube-like structure inserted into an affected vessel and fixed in place. The stent may serve to maintain a patent vessel lumen, may serve as structural support for the vessel, and/or may serve as an attachment/seal for a graft. A graft typically takes the form of a flexible tube or sleeve which is at least somewhat fluid-tight (although varying degrees of permeability may be desirable for a variety of reasons). When secured within a vessel using stents (a single stent the length of the graft, a pair of stent segments at the ends of the graft, or multiple stent segments spaced along the length of the graft), the graft becomes a surrogate vessel-within-a-vessel, and bears the brunt of the intravascular fluid pressure. It has become common practice to bridge damaged vessel segment using a sufficiently long graft secured within the vessel with stent segments.
Complications arise, however, when vessel damage occurs near a vessel branch point. More elaborate, multi-component devices are required to both shield the damaged vessel portion while maintaining blood flow through the main and branch vessels. Such devices are described in the following patents and references cited therein. Each of the following patents is hereby incorporated by reference as if fully set forth herein: U.S. Pat. No. 5,906,641; U.S. Pat. No. 6,093,203; U.S. Pat. No. 5,855,598; U.S. Pat. No. 5,972,023; U.S. Pat. No. 6,129,756; U.S. Pat. No. 5,824,040; U.S. Pat. No. 5,628,787; and U.S. Pat. No. 5,957,974.
Many of the prior-art devices are suitable for vessel branches where the branch vessel leaves the main vessel at a relatively small angle (less than about 45°, or example). For larger branching angles (as large as about 90° or even up to about 180°, for example) many prior art devices are not suitable. Such large branching angles occur at several potentially important repair sites (particularly along the abdominal aorta, at the renal arteries, celiac artery, superior and inferior mesenteric arteries, for example). Another drawback common to many devices of the prior-art is the need for transluminal access through the branch vessel from a point distal of the repair site. In many instances such access is either impossible (celiac artery, mesenteric arteries, renal arteries) or extremely difficult and/or dangerous (carotid arteries). Still other previous devices do not provide a substantially fluid-tight seal with the branch vessel, thereby partially defeating the purpose of the stent graft (i.e., shielding the repaired portion of the main vessel and/or branch vessel from intravascular fluid pressure).
It is therefore desirable to provide a bifurcated side-access intravascular stent graft and methods for fabricating and deploying the same, wherein the stent graft may be deployed transluminally to repair vessels having large-angle branch vessels (ranging from about 0° up to about 180°, for example). It is therefore desirable to provide a bifurcated side-access intravascular stent graft and methods for fabricating and deploying the same, providing a substantially fluid-tight seal with the main vessel and the branch vessel. It is therefore desirable to provide a bifurcated side-access intravascular stent graft and methods for fabricating and deploying the same, wherein the stent graft may be deployed transluminally without distal access through the branch vessel. It is therefore desirable to provide a bifurcated side-access intravascular stent graft and methods for fabricating and deploying the same, wherein the stent graft may be readily and accurately positioned relative to the branch vessel.